Mutation rate of VNTR loci in Mycobacterium tuberculosis: Response to Supply et al.

摘要

Their first two objections are based on our choice of the infinite alleles model (IAM) to describe the evolution of VNTRs and spoligotypes. Supply et al. claim that under the IAM all mutations are equally probable; in the case of VNTRs, most changes occur by loss or gain of a single repeat and in the case of spoligotypes, mutations occur by deletion of a single spacer. Thus, they argue, the IAM does not apply to these markers. We agree that most changes involve a single repeat or spacer, but we would like to clarify a misunderstanding of the IAM. This model gives each mutant a new label when it arises. It does not dictate that all classes of mutation are equally probable. It makes no commitment to the distribution of possible resulting genotypes and is compatible with any such distribution. This argument is therefore invalid.